1. Field of the Invention
The present invention relates to a disk array unit including a printed circuit board and a group of recording disk drives standing on the printed circuit board and arranged in parallel with one another on the front side of the printed circuit board.
2. Description of the Prior Art
In general, a disk array apparatus such as a RAID includes a disk array unit and a controller unit controlling the operation of the disk array unit. A plurality of recording disk drives such as hard disk drives (HDDs) are assembled in the disk array unit. The controller unit is designed to manage the operation of the disk array unit in accordance with the instructions from a host such as a server computer.
As disclosed in Japanese Patent Application Publication 9-146711, for example, the disk array unit includes hard disk drives mounted on the front side of a printed circuit board or a motherboard. The individual hard disk drives are coupled to corresponding connectors mounted on the surface of the motherboard. The motherboard is connected to the controller unit through an interface printed circuit board mounted on the backside of the motherboard. The individual hard disk drives are allowed to exchange data with the controller unit through the interface printed circuit board and the motherboard. The hard disk drives are designed to receive electric power from a power source unit likewise mounted on the backside of the motherboard.
The users are expecting an increased recording capacity of the disk array unit. However, the number of hard disk drives to be mounted on the motherboard necessarily depends on the size of the motherboard. In particular, the disk array apparatus of a so-called rack mount type should have the width standardized for racks. An increase in the width of the motherboard is restricted. The recording capacity of the disk array unit should be increased without enlarging the motherboard.
It is accordingly an object of the present invention to provide a disk array unit capable of efficiently arranging recording disk drives within a limited space.
According to a first aspect of the present invention, there is provided a disk array unit comprising: a printed circuit board; first connectors mounted on the front surface of the printed circuit board; at least a recording disk drive standing on the first connectors on the front surface of the printed circuit board; second connectors mounted on the back surface of the printed circuit board; and at least a recording disk drive standing on the second connectors on the back surface of the printed circuit board.
The disk array unit allows not only the front surface but also the back surface of the printed circuit board to receive the recording disk drives, so that the recording disk drives can efficiently be incorporated within the limited space, as compared with a conventional disk array unit. It is possible to realize an increased recording capacity of the entire disk array unit without enlarging the printed circuit board or adding another printed circuit board.
Preferably, the space between the adjacent second connectors is set larger than the space between the adjacent first connectors. The disk array unit of this type enables the space between the recording disk drives on the second connector to be set larger than the space between the recording disk drives on the first connector. A larger quantity of air can be introduced into spaces between the recording disk drives on the back surface of the printed circuit board as compared with those on the front surface. The recording disk drives on the back surface of the printed circuit board can sufficiently be prevented from suffering from an excessive increase in temperature even with the introduced air which has absorbed heat from the recording disk drives on the front surface.
A through hole may be defined in the printed circuit board. The through hole allows a fluent flow of air between a space along the front surface of the printed circuit board and a space along the back surface of the printed circuit board.
For example, the disk array unit may further comprise: an enclosure defining a front side space containing the recording disk drive standing on the front surface of the printed circuit board, said enclosure defining a backside space containing the recording disk drive standing on the back surface of the printed circuit board; and a ventilator mechanism moving air from the front side space to the backside space. The disk array unit of this type contributes to prevention of an excessive increase in the temperature of the individual recording disk drives in a relatively simple and cheap manner.
According to a second aspect of the present invention, there is provided a disk array unit comprising: a printed circuit board; first recording disks kept in a standing attitude on the front surface of the printed circuit board in parallel with one another, said first recording disk drives spaced by a first distance; and second recording disks kept in a standing attitude on the back surface of the printed circuit board in parallel with one another, said second recording disk drives spaced by a second distance different from the first distance.
The disk array unit allows not only the front surface but also the back surface of the printed circuit board to receive the recording disk drives in the same manner as described above. Accordingly, the recording disk drives can efficiently be incorporated within the limited space, as compared with a conventional disk array unit. It is possible to realize an increased recording capacity of the entire disk array unit without enlarging the printed circuit board or adding another printed circuit board. Moreover, a larger quantity of air can be introduced into spaces between the recording disk drives arranged at locations spaced by a larger distance. The recording disk drives spaced by the larger distance can sufficiently be prevented from suffering from an excessive increase in temperature even if the heated air is introduced in the space containing the recording disk drives.
The disk array unit of this type may further comprise: an enclosure defining a front side space containing the first recording disk drives on the front surface of the printed circuit board, said enclosure defining a backside space containing the second recording disk drives on the back surface of the printed circuit board; and a ventilator mechanism moving air from the front side space to the backside space. The disk array unit of this type contributes to prevention of an excessive increase in the temperature of the individual recording disk drives in a relatively simple and cheap manner.
In this case, the second distance is preferably set larger than the first distance. The disk array unit may allow the air to flow through the front side space to the backside space. The air which has absorbed heat from the first recording disk drives is introduced into the backside space. A larger quantity of the air can easily be introduced into spaces between the second recording disks spaced by the second distance larger than the first distance in the backside space. Accordingly, the second recording disk drives can be prevented from suffering from an excessive increase in temperature even if the heated air is introduced in the backside space.
Here, a through hole may be defined in the printed circuit board. The through hole allows a fluent flow of air between the front side space on the front surface of the printed circuit board and the backside space on the back surface of the printed circuit board.
The disk array unit of the first and second aspect may be incorporated within a rack, for example. In this case, the aforementioned enclosure of the disk array unit may be received on the rack. As conventionally known, the rack may also receive a controller unit managing the operation of the disk array unit, an electronic apparatus such as a host computer, a switching router, and the like, connected to the controller unit.